Silk screen machine



Nov. 23, 1954 R. J. SHQEMAKER 2,694,973

SILK SCREEN MACHINE Filed July 26, 1952 4 Shees-Sheet l FIG. Il

Nov. 23, 1954 Filed July 26, 1952 FIG.2

R. J. SHOEMAKER SILK SCREEN MACHINE 4 Sheets-Sheet 2 INVENTORS ROBERT J.SHOEMAKER HIS ATTORNEYS NOV? 23, 1954 R. J. sHoEMAKER SILK SCREENMACHINE 4 Sheets-Sheet 3 Filed July 26, 1952 INVENTOR ROBERT J.SHOEMAKER HIS ATTORNEYS Nov. 23, 1954 R. J. SHCI-:MAKER 2,694,973 SILKSCREEN MACHINE Filed July 26, 1952 4 Sheets-Sheet 4 FIG. 9

INVENTOR ROBERT d. SHOEMAKER BY ma my XM HIS ATTORNEYS United StatesPatent Oce 2,694,973 Patented Nov. 23, 1954 SILK SCREEN MACHINE RobertJ. Shoemaker, Dayton, Ohio, National Cash Register Company, poration ofMaryland assignor to The Dayton, Ohio, a cor- This invention relates toa semi-automatic machine for carrying out a silk screen process.

An object of the invention is to provide a semi-automatic machine whichincludes an indexing table on which blank articles are fed to a silkscreen, where a squeegee is automatically passed over the screen toprovide a silk screen impression on the article.

A specific object of the invention is to provide a turntable on whichilat articles are positioned by an operator and which is automaticallyturned to position the article beneath a silk screen, where a squeegeesupplied with ink passes over the silk screen to make an impression onvthe article, whereupon the table is indexed to position a new blankbeneath the screen, and the printed article is moved to a station wherean operator can remove it.

A specific object of the invention is to provide a mechanism foroperating a squeegee over a silk screen and to provide an ink well intowhich the squeegee is dipped prior to the silk screen operation.

Another specific object of the invention is to provide means foradjusting the squeegee so that the proper contact can be maintainedbetween the silk screen and the squeegee.

Another speciiic object of the invention is to provide mechanism forautomatically oscillating a squeegee, and a means for holding thesqueegee out of contact with the silk screen while the squeegee ismoving in one direction and to lower the squeegee into contact with thesilk screen during its return movement.

With these and incidental objects in View, the invention includescertain novel features of construction and combinations of parts, apreferred form or embodiment of which will be hereinafter described withreference to the drawings which accompany and form a part of thisspecitication.

Of said drawings:

Fig. 1 is a top plan view of the silk screen machine.

Fig. 2 is a side elevation of the machine shown in Fig. l.

Fig. 3 is a cross section taken on the line 3-3 in Fig. 1, looking inthe direction of the arrows.

Fig. 4 is a top plan View of the frame for mounting the silk screen.

Fig. 5 is an elevational View showing the squeegee and the manner ofadjusting it.

Fig. 6 is a detail top plan View of the Geneva gear operating mechanismfor turning the indexing table.

Fig. 7 is an elevational view, partly in cross section, taken on line 77 of Fig. 2.

Fig. 8 is a detail plan View showing the cam for actuating the silkscreen supporting frame.

Fig. 9 is a detail plan view showing the cam for raising and loweringthe squeegee.

General description The machine illustrated herein is a mechanism forperforming silk screen operations which have heretofore been done byhand. In the prior process, the silk screen is manually positioned overthe articles to be printed, and the squeegee is manually passed over thesilk screen to make a printed impression by hand. Hand-operated silkscreening, while very satisfactory, has the drawback of non-uniformresults. When a silk screen process is used for producing large numbersof articles, the hand method results in a high percentage of rejectswhen the article is to be used in an environment requiring extremeaccuracy. The present machine includes an indexing table on which thearticles to be printed upon are positioned by an operator, and the tableis indexed intermittently to position the article below the silk screen.ln the present embodiment, two articles are printed during one stroke ofthe squeegee. A Geneva gear operating mechanism is used to obtain theintermittent operation of the indexing table, which mechanism provides arest in the rotation of the indexing table long enough to perform thesilk screen operation. The squeegee is mounted on a reciprocating barwhich is controlled to be dipped into a well of ink and raised out ofthe well and then moved into its operating position. During the returnstroke of the squeegee, the squeegee is in lowered position in properengagement with the silk screen to force the ink through the screen tomake the printed impression on the articles below the screen. As thesqueegee approaches the end of its movement, it is raised over a darnand thereafter lowered into the well to dip fresh ink from the well forthe next cycle of operation. During the return stroke of the squeegeewhile it is not engaged with the screen, the table is indexed to feedthe printed articles from beneath the screen and to position new blankarticles therebelow. Before the indexing operation begins, a mechanismoperates to raise the screen out of contact with the articles, and,after the indexing table comes to rest in the printing position, thescreen is again automatically lowered into proper contact with thearticle to be printed.

Detailed description The mechanism is mounted on a table 2t), which maybe mounted on any desired standard. Mounted in suitable bearings in theplate 29 are three drive shafts, 21, 22, and 23. Secured to the lowerend of said drive shafts, adjacent the under side of the plate 2d, aregears 24, 25, and 26, respectively. The diameters of the gears 24, 25,and 26 are alike, so that, during each cycle of a machine operation,each of the shafts 2l, Z2, and 23 receives one complete rotation. Asuitable power mechanism, such as an electric motor, provided with apinion, may be in mesh with any one of the three gears 24, 2S, or 26,through which the mechanism comprising the shafts 2l, 22, and 23 isdriven.

Also supported in a suitable bearing in the plate 20 is a stud 27, onwhich the index turntable 2S is mounted for rotation. A bearing H29 ismounted on the upper face of the index turntable 2S and is provided witha recess into which a stub 30 on the upper end of the stud 27 ismounted. A bushing 3i provides a bearing for turning the indexing table28 on the shaft 27.

Mounted beneath the turntable 28 is a Geneva gear 29. The Geneva gear 29is secured to the turntable 28 by suitable screws 32.

Mounted on the upper end of the shaft 2l is a disc 35 (Figs. 2, 3, and6), on which is provided a stud 36 for actuating the Geneva gear 29.When the disc 35 is rotated clockwise (Fig. 6), the stud 36 enters anotch 37 in the Geneva gear to rotate the latter, and, when theturntable 28 has moved to position the article beneath the silk screen,the stud 36 moves out of the notch 37. A locking disc 38, engaging asurface 39 of the Geneva gear, normally locks the Geneva gear and theturntable in fixed position. A notch 40 in the disc 33 providesclearance for the Geneva gear, and the outer periphery 41 of the lockingdisc 38 locks the Geneva gear while the locking disc is rotated to bringthe stud 3e into engagement with the next notch 37.

A silk screen frame 45 (Figs. 3 and 4), later described in detail, isadjustably mounted on a floating bar 46 (see also Fig. 7). The floatingbar 46 is guided in its upand-down movements by two pilot studs 47,carried by a cross bar 48, supported on two standards 49, secured to theplate Ztl by any convenient means, such as the screws 50 (Fig. l). Thepilot studs 47 project downwardly into guide holes in the floating bar46. A spring 51 surrounds each pilot stud 47 to maintain a pair of campins 52 and 53 (see also Fig. 8) in engagement with cams 54 and 55,respectively, formed on a cam disc 56, which control the extent andtiming of the up-and-down movements of the floating bar 46. The cam disc56 is pinned to the shaft 22 and is rotated one complete rotationforeach machine cycle.

The oating bar 46 has secured thereto a frame for removably receivingthe silk'screen frame 45 and comprises two angle side pieces 57 and 5S(Fig. 4), connected by a front piece 59. The frame comprising the pieces57, 58, and 59 is secured together by screws 60 and to the floating bar46 by screws 61, so that this frame moves up and down with the lloatingbar 46.

The right-hand wall (Figs. 3 and 4) of the silk screen frame 45 isprovided with a groove 62, which slides on a rail 63 formed on thefloating frame 46, so that the silk screen frame may be adjustedlaterally thereon, to properly align the silk screen with the article tobe printed upon. The silk screen frame 45 is held in proper alignment onthe rail 63 by set screws 64 and 65, which pass through and are threadedin the pieces S and 57, respectively, of the silk screen framesupporting assembly. A further set screw 66 holds the silk screen framein engagement with the rail 63, and set screws 67, threaded in thefloating bar 46, provide a means for limiting the adjustment of theframe on the rail 63 and form an abutment for the silk screen when theset screw 66 is tightened thereagainst.

The invention is illustrated herein for printing target indicators suchas those shown in the United States Patent to Frederick L. Fuller, No.1,163,748, issued December 14, 1915. As disclosed in said patent,indicator targets having various characters thereon are used in cashregisters and accounting machines, and a large number of such duplicatetargets are in use. The invention provides a novel means to facilitatethe printing of such targets and to produce the targets with a minimumof rejects due to improper alignment and other imperfections that areinherent in hand silk screen operations. As illustrated herein, twotargets are printed during the same machine cycle, and the silk screenstencil, as illustrated in Fig. 4, is cut to print two targets. Theaccuracy and alignment of the printing on the targets is important incash registers and accounting machines, in that, when the targets are inuse in the machine, they must be in perfect alignment for the sake ofgood appearance. The set screws 64, 65, 66, and 67 permit the adjustment0f the silk screen to get the proper registration. After a sample targethas been screened, a gauge is provided to determine whether or not thesilk screen frame 45 is in proper alignment, and adjustments can be madeby use of these set screws and according to the requirements.

A well 70 is removably mounted on the silk screen frame 45 by means ofscrews 71 engaging ears on the well 70. A dam 72 prevents the ink fromowing out of the well to the screen. The silk screen 73 is stretched onthe silk screen frame 45 by means of a four-sided frame 74, which titsinto recesses in the silk screen frame 45, as shown in Fig. 3.

The up-and-down movements of the frame 45 are controlled by the cams 54and 55, which engage the aforementioned cam pins 53 and 54,respectively. When the cam plate 56 is rotated, the cam rails 54 and 55,engaging the cam pins 52, raise and lower the silk screen frame 45 atthe proper times.

A rubber squeegee 80 (Figs. 3 and 5) is provided for wiping over thesilk screen. inasmuch as two characters are printed at the same time ontwo individual targets, the squeegee t) is divided into two sections bycutting a notch 81 in its center, as clearly illustrated in Fig. 5. Eachsection of the unnotched portion of the lower end of the squeegee iswide enough to wipe over the stencil of each target. The squeegee 30 issupported in a bearing S2, which is pivotally mounted on a short shaft83, carried by two bearings 84. The bearings 84 are mounted on a slidingframe comprising the two plates 85 (Fig. 5), which in turn areadjustabiy mounted on a plate 86 connected to an oscillating rod 37,connected to a connecting rod 88 by set screws S9, or in any otherdesired manner. The right-hand end of the oscillating rod 87 is providedwith a slot 90, sliding on a stud 91, carried by a bar 92, supported onthe cross bar 93 of two standards 94. The standards 94 are supported onthe table 20 by means of screws 9S (Fig. l).

The bar 33 is slotted to receive a bar 96, having a hole to receive aformed pin 97, carried by a plate 98. A plate 9S is secured to the upperend of the shaft 23.

A cross bar 100 is mounted on the cross bar 4S and is' provided with anopening in which a cam pin 101 loosely fits. The oscillating rod 87normally rests on the top of the cam pin 101, and the latter rests on acam 102 (see also Fig. 9), secured to the `upper end of the shaft 22.The cam disc 102 is provided with a cam rail 103, which controls theextent and timing of the up-and-down movement of the oscillating rod S7and through said rod controls the up-and-down movements of the squeegee80. Spring-pressed studs 10S, carried in a housing 104, maintain theoscillating rod 87 in constant Contact with the cam pins 101. Thehousing 104 is mounted on the cross bar 100. Springs 105, engagingshoulders on the studs 103, maintain the under side of the oscillatingrod 87 in engagement with the top of the cam pin 101 and the latter inengagement with the cam plate 102.

A set screw 106 is provided to maintain the bearing 82 and, therefore,the squeegee 80 in the proper angular set position to provide a fineadjustment for the squeegee in respect to the position in which thesqueegee engages in the ink well and also with the silk screen justprior to the printing operation. An adjusting screw 107, having a collar109, engaging a notch in the plate 86, provides a means for adjustingthe frame holding the squeegee up and down on the bar 86, so that theproper pressure can be maintained on the silk screen during the printingoperation.

The targets 110 are positioned on the index table and are accuratelyspaced thereon by locating blocks 111 and by locating pins 112. Asillustrated in the Fuller patent, the targets 110 are notched at one endto fit over the blocks 111 and are provided with shoulders which engagethe locating pins 112. After the targets are placed in position, theyare so held by permanent magnets 115, which hold the targets 110 flatagainst the station block 114. rl`he station blocks 114 are suitablysecured in their proper location by screws 115.

As illustrated herein, the index table is provided with twelve stations.The invention is not limited to an indexing plate of twelve stations,since either'more or less stations can be provided, depending upon thework to be printed and the speed at which the machine is to be operated.Therefore, the twelve stations illustrated herein are merely for thepurpose of disclosing the invention.

Operation The sequence of operations of the machine is as follows,assuming that the machine starts from the position illustrated in thedrawings, which position is when the stud 36 of the Geneva drivemechanism is just about to enter the slot 37 in the Geneva gear 29. Atthis stage of the cycle of operation, the squeegee 50 is in itsleft-hand position (Fig. 3) and in the position in which it has beenraised out of the ink well and is about to be returned into itsoperating position. Also, at this time, the silk screen frame 45 is in araised position, so that, upon operation of the Geneva gear 28, thescreen will be out of contact therewith. Let it be assumed that theblank targets are on the index plate and the index table begins to move.While the index table is moving into its new position, the pin 97, beingrotated by the plate 98, moves the oscillating rod 87 toward the right(Fig. 3) to position the squeegee in the right-hand end of the frame. Bythe time the squeegee (iti reaches its right-hand position, the silkscreen frame will have been lowered by the cams S3 and 54, and the cam102 lowers the squeegee into contact with the silk screen. Thereupon thesqueegee is moved forward toward the position illustrated in Fig. 3 bythe pin 97 on the cam plate 9E, which cam plate makes one completesqueegee 80 reaches its right-hand position, the silk screen frame willhave been lowered by the cams 53 and 54, and the cam 102 lowers thesqueezee into contact with the silk screen. Thereupon th esqueegee ismoved forward toward the position illustrated in Fig. 3 by th epin 97 onthe cam plate 9S, which cam plates makes one complete rotation for eachcycle of operation of the machine, during which the connecting rod ismoved back and forth. Just before the squeegee reaches the dam 72, thecam 102, acting on the pin 101, raises the oscillating rod 87, causingit to pivot on the stud 91 and raise the squeegee so that it can passover the dam. Immediately after the squeegee passes over the dam 72, thecam 102 again permits the springs 105, acting on the cam pin 101', tolower the squeegee into the well to dip the squegee into the ink and'immediately raise the squeegee out of the well and into the positionshown in Fig. 3, whereupon the mechanism will be in position for anothercycle of operation.

The cycles of operation are continuous. An operator inserts blanks onthe indexing stations of the index plate 28 just before the blanks movebeneath the screen, and, as the printed targets move out from under thescreen, another operator removes the printed targets and positions themin drying racks.

By providing the fine adjustments for the silk screen frame 45 and forthe squeegee 80, the machine will silkscreen the targets so efficientlythat only a very few rejects are found. In addition to the reducednumber of rejects that are found as compared with the hand method, themachine can silk-screen as many targets as seven operators normallyproduce by hand. Therefore, the machine is adapted not only for bettersilk screen work but also for a greater production per man hour.

While the form of mechanism shown and described herein is admirablyadapted to fulfill the objects primarily stated, it is to be understoodthat it is not intended to contine the invention to the one form orembodiment disclosed herein, for it is susceptible of embodiment invarious other forms.

What is claimed is:

1. In a machine of the class described, the combination of anintermittently rotatable indexing table; a plurality of stations on thetable for receiving articles on which characters are to be stenciled bythe silk screen process; a silk screen; a silk screen frame forsupporting the silk screen; a squeegee for performing the silk screenstenciling process; a oat support for the silk screen frame; a

reservoir of ink in the frame; an actuating means to actuate thetsqueegee to dip the squeegee into the reservoir and thereafter raise thesqueege out of the reservoir; oscillating means to move the squeegeeinto a retracted position after the squeegee has been raised out of thereservoir; and means to lower the squeegee into contact with the silkscreen, said oscillating means thereafter operable to move the squeegeeacross the surface of the silk screen to perform the silk screenstenciling operation.

2. In a machine of the class described, the combination of a silk screenframe; a table for receiving articles on which characters are to bestenciled by the silk screen process; a silk screen; a frame forsupporting the silk screen; a floating support for the frame; asqueegee; a reservoir of ink; an oscillating member on which thesqueegee is carried; actuating means to lower the oscillating memberwhen the squeegee is opposite the ink reservoir to dip the squeegee intothe ink and to raise the squeegee out of the reservoir after beingdipped into the ink; and operating means to retract the oscillatingmember after the squeegee has been raised,v said actuating meansthereafter lowering the squeegee into contact with the silk screen, saidoperating means adapted to move the squeegee across the silk screen tostencil a character on the article below the screen.

3. In a machine of the class described, the combination of a silk screenframe; a table for receiving articles on which characters are to bestenciled by the silk screen process; a silk screen; a frame forsupporting the silk screen; a floating support for the frame; asqueegee; a reservoir of ink; an oscillating member; an adjustable slideon the oscillating member; a bearing on the slide to support thesqueegee; an adjusting screw to adjust the slide on the oscillatingmember, whereby the squeegee is adjusted in relation to the silk screen;actuating means to lower the oscillating member when the squeegee isopposite the ink reservoir to dip the squeegee into the ink and to raisethe squeegee out of the reservoir after being dipped into the ink; andoperating means to retract the oscillating member after the squeegee hasbeen raised, said actuating means thereafter lowering the squeegee intocontact with the silk screen, said operating means adapted to move thesqueegee across the silk screen to stencil a character on the articlebelow the screen.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 1,922,710 Owens Aug. 15, 1933 2,229,346 Shurley Jan. 2l, 19412,339,423 Pollard Jan. 18, 1944 2,555,096 Reinke May 29, 1951

